Apparatus for controlling cracking stills



Nov; 6, 1928: 1,690,243-

- W. C. PARRISH I APPARATUS FOR CONTROLLING CRACKING STILLS Filed April 16, 1924 15 4 r [WM v 2a ,a1 2 U n E] l lv n llr Grime/1;; XL

Patented Nov. 6, 1928.

UNITED STATES PATENT OFFICE.

WILLIAM C. PARRISH, OF PORT ARTHUR, TEXAS, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE TEXAS COMPANY, OF NEW YORK, N. Y., A CORPORATION 012' DELAWARE.

APPARATUS FOR CONTROLLING TRACKING STILLS.

Application filed April 16, 1924. Serial No. 706,797.

This invention relates to means for controlling and regulating the operations of cracking stills wherein petroleum oils or other hydrocarbon products are subjected to cracking or decomposition for the production of the lighter oils, such as gasoline and the like. More particularly the invention relates to means for indicating the proper'time when a run on a given apparatus should be 10 terminated or the operating conditions therein altered.

In carrying on the cracking operation there is formed, in addition to the light products desired, certain heavier products including more or less carbon. As a general rule the longer a given quantity of oil is subjected to the cracking operation the greater will he the proportion of carbon or coke produced. The cracking operation can be carried on with certain quantities of carbon and coke present. without appreciable injury to the metallic surfaces subjected to direct heat. As a run is continued, however, the accumulations of carbon or coke may eventually become so large as to create liabilit of grave danger to the apparatus employe and the difliculty in ordinary practice has been that there is no means of observing the conditions obtaining within the still or vessel being used. In

accordance with my invention an element is provided which is adapted to have movement in contact with the body of oil undergoing" conversion and means is provided for measuring the load imposed on the operating means for the movable element. Thus the cracking apparatus is equipped with stirring or agitating mechanism or with means for scraping the walls of the vessel and means for indicating the load imposed on the prime if) mover operating the stirring, agitating or scraping mechanism. As the accumulation of carbon and coky material increases, the load on the scraper or stirrer increases and by providing means for indicating the load it is 5 thus possible to maintain an accurate observation of conditions within the cracking apparat-us so that the operator may be advised of the roper time to terminate a run or to alter con 'tions within the apparatus.

A preferred embodiment of the invention is illustrated in the accompanying drawing which is a diagrammatic sectional elevation of the apparatus.

10 indicates the cracking apparatus wherein the hydrocarbon oil is subjected to cracking temperatures. The cracking operation is commonly carried on under superatmospheric pressure and is usually accompanied with distillation, although in some cases the cracking iscarried on without distillation in closed converters or autoclaves. The vessel 10 thus represents a pressure still or converter adapted to be subjected to the conditions as to temperature and pressure that are desired to effect cracking. The vessel is provided'with agitating, stirring, or scraping elements which are diagrammatically indicated at 11 and which may assume many diverse forms as is well known by those skilled in the art. The elements 11 may, for instance, bearranged to scrape or' remove carbon or coke deposits from the wall of the converter or they may be of a nature suitable for stirring or agitation as distinguished from scraping. The elements 11 are shown as being carried lib on a shaft 12. A motor or other suitable source of power 13 is provided for supplying power to the shaft 12. The motor shaft 14:, as illustrated, carries a spur gear 15 which meshes with the gear 16 on an intermediate shaft 17 which is geared to the shaft 12 by bevel pinions 18 and 19.

The motor 13 is provided with means for operating same, which for purposes of illustration is shown as including a circuit system of the three-phase type embracing the leads 20, 21, and 22 which extend through a switch 23 to a suitable source of power, not shown. One of the leads, as for example the conductor 22, is in circuit with an indicator, such as the load indicator or ammeter 24. It is generally desirable to provide alarm or signailing means, or contro apparatus arranged to be actuated when the load on the motor exceeds a predetermined amount. Thus the conductor 22 may be in circuit with a primary winding of a current coil 25 arranged to operate a solenoid 26 which is equipped with a core or plunger 27. The conductor 22 has a branch line 22 and the conductor 21 has a branch line 21 which branch lines are adapted to be placed in electrical contact by a switch at 28 that is actuated by the plunger 27 A set screw or other adjusting means 32 is provided to regulate the position of the plunger 27 so that it will be actuated to close the switch 28 upon a predetermined load on the motor 13. In circuit with one of the branch lines, as 21". is a bell 29 or other signalling or alarm mechanism. Leads 30 and 31, which extend to suitable control apparatus, may be provided. The control apparatus may embrace means for operating valves,

or converter 10 or terminate the run, or thechange of conditions or'termination of the run may be accomplished automatically by means in circuit with the leads 30 and 31.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore, only such limitations should be imposed as are indicated in the appended claims.

As a specific example of my invention it may be stated that in one case a cracking still was operated with continuous operation of stirring mechanism positioned within the still.- When operating conditions were established the amount of power consumed in operating the stirring mechanism was approximately 2500 watts. The run was continued for a number of'days during which time the amount of power consumed in operating the stirring mechanism continued to increase slightly until it reached approximately 3000 watts. During this period the chart of the recording instrument did not show any violent fluctuations and, in fact, the indication on the chart was in general a straight line. After carrying on therun for a number of days in this manner, the amount of power consumed suddenly increased a material extent and the recording instrument showed violent fluctuations, as follows l Watts The great increase in the amount of power employed and also the violent fluctuations in the amount required indicated the accumulation of coke or carbon in the still and showed the desirability of terminating the run or of flushing out the still.

What I claim is:

1. In the conversion of higher boiling hydrocarbons into lower boiling ones, the process that comprises maintaining a body of oil at a cracking temperature to cause the formation of lighter hydroc rbons and carbon, agitating said body of ll by means of a power operated agitating means, measuring the power employed in operating said agitating means, and continuing the operation with resultant accumulation of carbon and consequent increased resistance to the movement of the agitating means and stopping the run when the increased resistance, as measured by the amount of power employed in operating the agitating means, reaches a predetermined amount indicating the excessive production of carbon.

2. In the conversion of higher boiling hydrocarbons into lower boiling ones, the process that comprises maintaining a body of oil in a chamber at a cracking temperature to cause the formation of lighter hydrocarbons and carbon, continuously scraping the interior wall of said chamber by power operated scraping mechanism, measuring the power employed to operate said mechanism and continuing the operation with resultant accumulation of carbon and consequent increased resistance to the movement of the scraping mechanism and stopping-the run when the increased resistance, as measured by the amount of power employed in operating the scraping mechanism, reaches a predetermined amount indicating the excessive production of carbon.

In witness whereof I have hereunto set my hand this 31st day of March, 1024.

W. C. PARRISH.

(ill 

